Section 6 — Motion Control Tutorial
6 - 7
+
Error
Position
0
Hysteresis
–
Figure 6.2-7 — Hysteresis Plot
The error plot in reverse direction is identical with the first one but seems
to be shifted down by a constant error. This constant error is the
Hysteresis
of the system.
To justify a little more why we call this error
Hysteresis
, let’s graph the
information in a different format (Figure
6.2-8). Plotting the real versus the
ideal position will give us a familiar
hysteresis
shape.
Real
position
Trajectory (ideal position)
ideal plot
real plot
Figure 6.2-8 — Real vs. Ideal Position
6.2.9 Pitch, Roll, and Yaw
These are the most common
angular
error parameters for linear translation
stages. They are pure mechanical errors and represent the rotational error
of a stage carriage around the three axes. A perfect stage should not rotate
around any of the axes, thus the
Pitch
,
Roll
,
and
Yaw
should be zero.
The commonly used representation of the three errors is shown in Figure
6.2-9.
Pitch
is rotation around the Y axis,
Roll
is rotation around the X axis
and
Yaw
around the Z axis.
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